1. Field of the Invention
The present invention relates to an LC composite component, and more particularly, it relates to a chip-type LC composite component which is applicable to a noise filter in a high-frequency circuit.
2. Description of the Background Art
In general, a filter device for filtering high frequency noise signals comprises at least one inductor and at least one capacitor. For example, U.S. Pat. No. 4,320,364 granted to Sakamoto et al. and issued on March 16, 1982 discloses an LC composite component which enables treatment of such an LC filter as one electronic component.
The '364 patent discloses various embodiments. For example, FIG. 16 of the said patent concretely shows the structure of the so-called T-type filter circuit, which is formed as a single electronic component comprising one capacitor C and two inductors L1 and L2, as shown in FIG. 6. In this structure, a pair of opposite capacitor electrodes are provided on both surfaces of a dielectric substrate, to form the capacitor C. A substantially U-shaped input/output lead wire is soldered to one of the capacitor electrodes, while both legs thereof are inserted in ferrite bead members respectively. A ground lead wire is soldered to the other capacitor electrode.
The LC composite component thus formed has three lead wires in consequence. In order to mount the LC composite component on a printed circuit board, for example, the three lead wires are inserted in holes provided in the printed circuit board respectively, to be soldered to conductive patterns provided on the printed circuit board.
However, the LC composite component of the aforementioned structure has such a problem on manufacture that the assembly operation thereof is complicated. Further, it is difficult to reduce the size of the LC composite component since the dielectric substrate employed therein has a relatively wide major surface. In addition, the LC composite component having the aforementioned structure is mounted on the circuit board in an upwardly directed state, and hence a space for mounting the same is increased. Thus, it is difficult to mount the LC composite component on the circuit board in high density.